In numerous assembly line operations, a plurality of objects are held in temporary storage on tracks prior to packaging into cartons. For example, paper towels wrapped in flexible packaging containers are lined up end to end in abutting relationship prior to packaging in large cardboard cartons. Standard devices for placing the towels in the cartons were satisfactory until manufacturers began offering different color towels. At first, the cartons were filled with towels having the same color and then repackaged by hand to obtain the selected color mix.
The first machines developed consisted of tracks with moving belts to provide the "live" storage of the towels. An arm pressed down upon the top of the towels to hold them until a control device signaled the arm to rise sufficiently to permit one or more towels to move forwardly.
Two problems were encountered; the flexible packaging around the towels became scuffed or torn by the moving belts while they were being held by the pressing arm, and counting control was not sufficiently accurate due to the inherent difficulty the mechanism had in "counting" the number of packages passing beneath the pressing arm while it was in the raised position. The difficulty lay in the fact that no device proved satisfactory in detecting the beginning of one package and the end of the preceeding package.
The use of air supporting and transporting mechanisms to convey the towel packages solved the scuffing problem caused by conveyor belts, but the problem of "counting" the packages was still unsolved.